1. Field of the Invention
The present invention relates to a pipe element used for a heat exchanger such as a gas-liquid or a liquid-liquid non-contact type heat exchanger and a heat exchanger employing such pipe elements.
2. Discussion of Background
FIG. 6 shows the structure of a conventional heat-exchanging pipe. The pipe is formed in a zig-zag form having a plurality of U-shaped bent portions and a plurality of linear portions connected to both sides of the U-shaped bent portions so that the linear portions extend in parallel to each other.
In the conventional heat exchanger, when the zig-zagged pipe is to be installed in the horizontal direction, it is necessary to give some difference in height between the inlet and outlet of the zig-zagged pipe so that liquid in the pipe can be easily drained. Such construction, however, places each of the linear portions of the pipe horizontally with respect to the ground on which the heat exchanger is set. Accordingly, it is unavoidable that some amount of the liquid remains in it even though the liquid in the zig-zagged pipe is to be drained.
Further, it sometimes happens that the zig-zagged pipe is deformed by an external force. In this case, a substantial amount of liquid remains in the deformed linear portion, which may cause the damage to the pipe when the remaining water is frozen in winter or when the pipe is at a cold place.